Radial sawing involves sawing elongated wedges of timber from a log so that the resulting wedges have two radial faces that are essentially formed by sawing the log along planes parallel to radii extending from a selected centre of the log along the longitudinal axis of the log.
Radial sawing logs allows for increased recovery of usable timber from a log and timber products with consistent growth ring orientation.
These advantages have been outlined fully by Hasenwinkle U.S. Pat. No. 3,903,943 and Knorr Australian Patent No. 623344, and Knorr U.S. Pat. No. 5,560,409.
Although radial sawing offers many theoretical and practical advantages, industry has not generally adopted or developed the method.
Prior art does not disclose a method for a production process involving radial sawing logs to wedges with the subsequent ability to produce backsawn boards, quartersawn boards, further divided radial wedges or trapezoidal timber sections if required. Prior art discloses sawing devices which appear cumbersome or which because of the use of multiple blades would be expensive to build and difficult to operate and maintain.
Also, none of these devices allow for the economical and practical sawing of logs with growth stresses. These stresses which are particularly strong in small diameter hardwood trees are adversely affecting the timber industry as old growth type forests are cut out and the timber resource comes increasingly from regrowth and plantation timbers.
Australian Patent No. 623344 does disclose a method for the production of radial wedges from all logs including logs that contain growth stresses. The method involves the mounting of logs in holding devices which hold the ends of the logs. These holding devices allow the log to be rotated along their longitudinal axis and for saw cuts to be made at predetermined angles basically from the outside to the centre along the length of the log. Although this has many advantages it does not provide a practical method of integrated operation that does not involve sawing of the end of the log or additional cuts to separate the wedges after the radial sawing process.